Establishment Of Index System Of Soil Series Classification For Stagnic Anthrosols In Changsha

Changsha is located in the middle reaches of the Yangtze River, which belongs to the mid subtropical monsoon humid climate. As the main rice producing areas, it has fertility soil and plentiful natural resources. Therefore, it is particularly important to do a good job of lower categories of Stagnic Anthrosols in Changsha.(1) According to the principles of soil series division, used mathematical statistics methods, selected the main indexes of the soil series classification, and established the index system of the soil series classification.For morphological characteristics, there are significant differences if the diversity among thickness of gley horizon reaches 2 times or more than 15cm; taking 30 and 60cm as the boundary, divided ferrimanganic mottling layer into three thicknesses, and divided it into two layers by 60cm. For physical and chemical properties, divided organic matter content of topsoil into three levels by 20 and 35g/kg; if the texture of topsoil is different, it is regarded as a significant difference.(2) Divided the higher categories of soil taxonomy of 12 soil profiles in Changsha, determined the diagnostic horizons and diagnostic characteristics of soils, these profiles included 1 suborder,3 groups and 3 subgroups.(3) Based on the higher categories, according to the particle size grade, mineralogical type, calcareous and acid-base reaction, and soil temperature.3 subgroups has been divided into 8 soil families.(4) Making use of the index system of soil series classification,8 soil families has been divided into 12 soil series and soil series retrieval is established as well.